Technical Abstract:
Although Bordetella bronchiseptica is now unquestionably accepted--along with toxigenic Pasteurella multocida--as one of the etiologic agents of swine atrophic rhinitis (AR), its economic impact on swine production may be underestimated by producers. Difficulties related to isolation and identification continue to exist and can mask the role of B. bronchiseptica ain disease. Additionally, anecdotal reports and results from several studies indicating that B. bronchiseptica is frequently found in older fattening pigs without clinical signs of respiratory disease have created the perception that detection in the absence of overt AR or pneumonia is of little consequence. However, a number of studies document decreased weight gain, increased days to market, and reduced feed efficiency attributable to B. bronchiseptica infection. The specific impact of B. bronchiseptica on a herd depends upon the particular environmental, management, and other factors unique to the operation in question. The recent trend towards large-scale, high density operations is likely to further affect the impact of this bacterium on swine production. Recognition of suboptimal performance may not be obvious when production data and environmental and management conditions are not carefully monitored. The presence of B. bronchiseptica in a herd also predisposes pigs to complicated respiratory infection involving additional bacterial and viral pathogens and can exacerbate the severity of disease. Recent research demonstrates that pigs co-infected with PRRSV and B. bronchiseptica suffer more severe respiratory disease and decreased weight gain than pigs infected with either agent alone. Producers should not ignore the presence of B. bronchiseptica in a herd but rather should take steps to manage its effects.